The present invention relates to a steering wheel, and more specifically to a steering wheel having an air bag.
Generally, the steering wheel of a vehicle includes an annular grip, a pad located in the center of the grip ring, and spokes extending from the grip ring to the center. A metal grip core is embedded in the grip, and a metal spoke core is embedded in the spokes. A surface layer formed, for example, of polyurethane covers the grip core and the spoke core. A boss plate is fastened to the distal end of a steering shaft by a nut. After the boss plate is attached to the steering shaft, an air bag device is installed in the steering wheel. Then, the pad is mounted over the air bag device.
In recent years, to improve the design of steering wheels, it has been proposed that the surface layer and the pad be formed integrally (Japanese Unexamined Utility Model Publication No. 2-133955). In the steering wheel of the Japanese Publication, an insert is embedded in the pad to prevent scattering of the pad when the air bag device is activated. According to this publication, the insert is held on the metal core by resin foam.
However, during inflation of the air bag, the resin foam may be broken, and the insert may separate from the metal core. Therefore, the pad may scatter when opened by the inflation of the air bag.